The radar-permeable member is mounted in the beam path of a radar radiator installed on a motor vehicle. This radome protects the radar emitter from environmental influences and at the same time covers the required open beam path with a defined geometry adapted to the wavelength range. It therefore ensures integration of the radar reflector into the homogeneous appearance of the vehicle without affecting its function. The radome can be embodied in the form of a design element and thus can contribute to the direct identification and characteristics of the vehicle.
DE 198 44 021 C2 describes a covering part made of plastic lying within the beam path of a radar device and having partial areas of metal visible from the outside, in which                the plastic part has a multilayer structure,        partial areas of metal are formed by an extremely thin layer vapor-deposited onto one of the layers which acts as a support,        said partial areas of metal are covered with, or vapor-deposited on, a transparent layer towards the surface side from which they are supposed to appear visible from the outside,        the metal layer is applied on the whole surface in the total area to be penetrated by the radar beams, and is covered by an opaque layer in those areas where it should not be visible from the outside,characterized in that the metal layer is made of indium and has a thickness in the nanometer range.        
JP 2008-24 254 A describes a structure and a method of manufacturing a radome for a motor vehicle distance warning radar. The radome described therein consists of a support, a design element and a surface layer. The design element is integrated in the support made of dark plastic, and provided with a thin, radar transparent, shiny metal layer. The surface layer is made of transparent plastic, which covers both the design element and the support.
The manufacturing method according to EP 0954052 B2 is very expensive. The design element is embedded into a negative mold in a radar and visually transparent cover plate, wherein said mold is provided with a metallic coating or a coating having a metallic shine, and said metallic coating or coating having a metallic shine has such a thickness that the electromagnetic radiation is reflected completely in the visible wavelength range, and the longer-wave radar waves pass through almost unhindered.
The known coverings/facings of distance warning systems are prepared by joining technology. In this method, air bubbles must be avoided (see EP 0954052 B1, [0012]) to ensure trouble-free radar passage. This leads to high cost, in addition, the visually transparent surface of the component must be coated with a hard coat in order to provide scratch protection, chemical and UV resistance. This coating also causes considerable costs.